MK Masterseal RCD sockets - won't reset.

[Timbo]

Hello everyone
I was wondering if anyone else has had problems with these sockets not resetting. I have a client with three of them for the purpose of servicing air handling units. Rarely used but just will not reset. Installed 5 years ago.

Regards, Tim.

 

[buzzlightyear]

is there any thing plugged in them?

 

[SparkyChick]

Do all three of them fail to reset or is it just the one?

The literature suggests they will trip (and I'm guessing not hold) if there is no supply, so it may be worth checking the supply is in good order and on.

Edit:- Scratch that assertion... they come in two flavours... trip on mains failure (active) and no trip on mains failure (passive), but I would still check the supply to ensure it's OK.

 

[Timbo]

Nothing plugged in.

Supply good - 241v L-N, L-E.
All 3 on one radial final circuit.
All failed.

I was doing EICR and came to test them - nothing doing.

I'm just going to quote for replacing with BG ones. Only thing is they are slightly narrower and it is surface conduit.

 

[buzzlightyear]

why would all 3 failed I wonder .and when did they fail ?

 

[Strima]

Had some MK RCD sockets fail in the past, was an unmanned site and they were never tested. All of them would trip and not reset, I just ended up replacing the lot, was four of them in total.

These were the metal clad ones but I would guess the gubbins are the same inside.

 

[Midwest]

Has the radial circuit been tested for faults?

 

[DPG]

Far too much of a coincidence if they have all failed at the same time. Could they have failed at different times and people just haven't been noticing?

 

[calpol91]

I might be showing my stupidity here, but is it possible there's a fault on the circuit itself? i only say this because just before Christmas, me and another lad were sent to replace a dozen or so at a factory, and the first one we did tripped. So we swapped it with another, that tripped. We went and did the others on different circuits and had no issues, that one, which was the only RCD socket on that circuit tripped every time.

We reported it and not sure if its been sorted or what the outcome was if it has been, this post just reminded me....

 

[marconi]

MK require residual current devices to be disconnected during IR tests to prevent damage to their electronic circuitry. Have IR tests been done recently?

See Section H in:

http://docs-europe.electrocomponents.com/webdocs/0e65/0900766b80e650c3.pdf

 

[mhar]

I 500v ir tested an rcd socket a while back and it didn't work after, I know it was working before because I was using a lamp plugged into it. Luckily I was upgrading the circuit to rcbo protection so it only cost me a replacement standard socket.
Must admit to now being nervous about testing when usb sockets are used and tend to link them out (to give a true ir reading of the conductors and to avoid any potential damage).

 

[Timbo]

[QUOTE="marconi, post: 1347093, member: 87486]Have IR tests been done recently?
[/QUOTE]

No. Went to check RCD operation and no deal.
No one would have been near it with an IR tester since EIC in 2012.

 

[marconi]

I wonder if you have a broken incoming conductor at the first socket, perhaps through over-tightening causing a fracture or, simply a loose grip by the screw and the conductor has sprung away from making contact in the terminal.

Or, a break somewhere between the first socket and the DB or in the DB.

Last, could you measure the N-E voltage at the DB please and tell us the type of supply ie: TT, TNCS or TNS.

A simple trial would be to take one of the four sockets, wire it to a 13 Amp plug and then plug in to a serviceable socket.

 

[ruston]

@Timbo . What was their specific job with air handling .
Is it possible the environment has affected them ie in a swimming pool plant room.

 

[Timbo]

@Timbo . What was their specific job with air handling .
Is it possible the environment has affected them ie in a swimming pool plant room.

External location - partial roof over area, provided for use of service personnel for lead lights, vacuum cleaners etc.

 

[ruston]

Ok. Have they been kept closed properly or subject to damp?

 

[ruston]

I'm just wondering despite not being used much that they have been tripped that many times in that environment that they have just given up the ghost.
Clients always describe the job well...

 

[static zap]

Saw 1x Rcd double socket ,die in 3yrs .(may have been cheap from sheds) ,cold flat roofed extension, near a compressor ..May be on to something with environment @ruston .
(as far as IR tests ... is it worth putting a warning on relevant CU circuit ?)